JP2006241468A - Lubricating oil composition for metal belt continuously variable transmission - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new lubricating oil composition for a metal belt continuously variable transmission capable of attaining a high inter-metal friction coefficient between a belt and a pulley. <P>SOLUTION: The lubricating oil composition for the metal belt continuously variable transmission comprises a lubricating base oil and, incorporated therewith, 0.005-0.2 mass% in terms of the phosphorus element amount, based on the composition, of a phosphorus compound represented by general formula (1), and 0.05-10.0 mass% of an ashless dispersant having a nitrogen content of at least 0.2 mass%. In the formula, R<SP>1</SP>and R<SP>2</SP>are each an alkyl group, a phenyl group or a cresyl group; R<SP>3</SP>is a hydrogen atom, an alkyl group, a phenyl group or a cresyl group; and X<SP>1</SP>, X<SP>2</SP>and X<SP>3</SP>are each an oxygen atom or a sulfur atom. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  TECHNICAL FIELD The present invention relates to a lubricating oil composition for a metal belt type continuously variable transmission, and more particularly, a lubricating oil composition for a metal belt type continuously variable transmission that is particularly excellent in friction characteristics between a belt and a pulley in a metal belt type continuously variable transmission. Related to things.

A metal belt type continuously variable transmission is a transmission that has a mechanism for transmitting torque by friction between a belt made of metal and a pulley, and changing the radius ratio of the pulley to change the energy. In recent years, it has come into the limelight as a transmission for automobiles.
As the lubricating oil used in this metal belt type continuously variable transmission, it is extremely important to have excellent friction and lubrication characteristics between the metal belt and the metal pulley, as well as the gears that extract torque and the lubrication for the bearings that support them. Performance as oil, performance as a hydraulic control medium for determining a gear ratio, that is, performance as hydraulic fluid is also required.
Further, in the case where the continuously variable transmission includes a forward / reverse switching wet clutch or a torque converter lock-up system, in addition to the above-described performance, performance for controlling the friction characteristics of the wet clutch is also required.
As described above, since various performances are required for the lubricating oil for the metal belt type continuously variable transmission, automatic transmission oil (ATF) is generally used. However, when ATF is used as a lubricant for a metal belt type continuously variable transmission, it is excellent in performance as a hydraulic fluid and in controlling the friction characteristics of a wet clutch, but the friction coefficient between the belt and pulley metal. Is not enough.
Therefore, the conventional metal belt type continuously variable transmission using the ATF has a limit in transmission torque capacity, and has a problem that it can be mounted only on a small automobile.

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a novel metal capable of exhibiting a high friction coefficient between the belt and the pulley when used in a metal belt type continuously variable transmission. An object of the present invention is to provide a lubricating oil composition for a belt type continuously variable transmission.

（（１）式中、Ｒ^１及びＲ^２は、それぞれ個別に、炭素数１〜６のアルキル基、フェニル基又はクレジル基を示し、Ｒ^３は水素原子、炭素数１〜６のアルキル基、フェニル基又はクレジル基を示し、Ｘ^１、Ｘ^２及びＸ^３は、それぞれ個別に、酸素原子又は硫黄原子を示す）
及び（Ｂ）窒素含有量が０．２質量％以上の無灰分散剤（以下、「（Ｂ）成分」という。）を、組成物全量基準で０．０５〜１０．０質量％含有してなるものである。 In order to achieve the above object, a lubricating oil composition for a metal belt continuously variable transmission according to the present invention includes (A) at least one phosphorus represented by the following general formula (1): Or a derivative of at least one phosphorus compound represented by the following general formula (1) (hereinafter referred to as “component (A)”) as a phosphorus element amount based on the total amount of the composition. 0.2% by weight,

(In the formula (1), R ¹ and R ² each independently represent an alkyl group having 1 to 6 carbon atoms, a phenyl group or a cresyl group, R ³ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, A phenyl group or a cresyl group, and X ¹ , X ² and X ³ each independently represent an oxygen atom or a sulfur atom)
And (B) 0.05 to 10.0% by mass of an ashless dispersant having a nitrogen content of 0.2% by mass or more (hereinafter referred to as “component (B)”). Is.

Further, the lubricating oil composition for a metal belt type continuously variable transmission according to the present invention has (C) a total base number of 20 to 500 mgKOH / in addition to the above-specified amounts of the components (A) and (B). g alkaline earth metal sulfonate (hereinafter referred to as “component (C)”) is contained in an amount of 0.01 to 0.5 mass% as the amount of alkaline earth metal element based on the total amount of the composition.
Moreover, the lubricating oil composition for a metal belt type continuously variable transmission according to the present invention has (D) a total base number of 20 to 500 mgKOH / in addition to the above-specified amounts of the components (A) and (B). g calcium phenate (hereinafter referred to as “component (D)”) is contained in an amount of 0.01 to 0.5 mass% as the amount of calcium element based on the total amount of the composition.

Further, the lubricating oil composition for a metal belt type continuously variable transmission according to the present invention may further include the specified amount of ((A) component, (B) component, and (C) component) in addition to the specified amount ( D) It contains a component.
In addition, the lubricating oil composition for a metal belt type continuously variable transmission according to the present invention contains the specified amounts of the components (A) and (B) and (E) zinc dithiophosphate (hereinafter referred to as “(E ) Component ”))).
The lubricating oil composition for a metal belt type continuously variable transmission according to the present invention contains (A) component, (B) component and (C) component in the specified amounts, and substantially contains (E) component. It is not contained in.
The lubricating oil composition for a metal belt type continuously variable transmission according to the present invention contains (A) component, (B) component and (D) component in the specified amounts, and substantially contains (E) component. It is not contained in.
The lubricating oil composition for a metal belt type continuously variable transmission according to the present invention contains the specified amounts of the components (A), (B), (C) and (D), and (E ) It does not contain a component substantially.
It is preferable that all or part of the component (B) is boron-modified succinimide.

  The lubricating oil composition for a metal belt type continuously variable transmission according to the present invention can transmit a high torque between a belt and a pulley, and can be mounted on a large automobile.

Hereinafter, the contents of the present invention will be described in more detail.
As the lubricating base oil in the lubricating oil composition for a metal belt type continuously variable transmission according to the present invention, any mineral oil and / or synthetic oil used as a base oil for ordinary lubricating oil can be used.
Specifically, as mineral oil, for example, a lubricating oil fraction obtained by subjecting crude oil to atmospheric distillation and reduced pressure distillation is subjected to solvent removal, solvent extraction, hydrocracking, solvent dewaxing, catalytic dewaxing, hydrogenation. Paraffinic and naphthenic oils, normal paraffins, and the like purified by appropriately combining purification, sulfuric acid washing, purification treatment such as clay treatment, and the like can be used.

The synthetic oil is not particularly limited, and specifically, for example, poly-α-olefin (1-octene oligomer, 1-decene oligomer, ethylene-propylene oligomer, etc.) and hydride thereof, isobutene oligomer and hydrogen thereof. , Isoparaffin, alkylbenzene, alkylnaphthalene, diester (ditridecyl glutarate, di-2-ethylhexyl adipate, diisodecyl adipate, ditridecyl adipate, di2-ethylhexyl sebacate, etc.), polyol ester (trimethylolpropane caprylate, trimethylolpropane) Pelargonate, pentaerythritol 2-ethylhexanoate, pentaerythritol pelargonate, etc.), polyoxyalkylene glycol, dialkyldiphenyl ether, Polyphenyl ether and the like can be used.
The kinematic viscosity of these lubricating base oils is not particularly limited and is arbitrary, but usually the kinematic viscosity at 100 ° C. is preferably 1 to 10 mm ² / s, more preferably ² to 8 mm ² / s.

The component (A) in the lubricating oil composition for a metal belt continuously variable transmission of the present invention is represented by at least one phosphorus compound represented by the following general formula (1) or the general formula (1). It is a derivative of a phosphorus compound.

(1) In the formula, R ¹ and R ² each independently represent an alkyl group having 1 to 6 carbon atoms, a phenyl group, or a cresyl group. Examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group (these alkyl groups may be linear or branched). Examples of the cresyl group include o-cresyl group, m-cresyl group, p-cresyl group and the like.
(1) In the formula, R ³ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, a phenyl group, or a cresyl group, preferably a hydrogen atom. Examples of the alkyl group having 1 to 6 carbon atoms include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, and a hexyl group (these alkyl groups may be linear or branched). Examples of the cresyl group include o-cresyl group, m-cresyl group, p-cresyl group and the like.
(1) In the formula, X ¹ , X ² and X ³ each independently represent an oxygen atom or a sulfur atom, preferably an oxygen atom.

As the component (A) of the present invention, it is important that R ¹ , R ² and R ³ are groups having a limited structure as described above, and the group defined by R ¹ , R ² or R ³ Otherwise, the friction characteristics between the belt and pulley metal deteriorate, which is not preferable.
In addition, as a derivative of the phosphorus compound represented by the formula (1), specifically, for example, a hydrogen phosphite (hydrogen phosphite) in which R ³ is a hydrogen atom in the formula (1) or Nitrogen-containing compounds such as amine compounds containing in the molecule only ammonia, hydrocarbon groups having 1 to 8 carbon atoms or hydroxyl group-containing hydrocarbon groups in phosphorus compounds such as hydrogenated thiophosphites (hydrogenthiophosphites) Examples thereof include salts obtained by reacting a compound to neutralize part or all of the remaining acidic hydrogen.

  Specific examples of the nitrogen-containing compound include ammonia; monomethylamine, monoethylamine, monopropylamine, monobutylamine, monopentylamine, monohexylamine, monoheptylamine, monooctylamine, dimethylamine, methylethylamine, Alkylamines such as diethylamine, methylpropylamine, ethylpropylamine, dipropylamine, methylbutylamine, ethylbutylamine, propylbutylamine, dibutylamine, dipentylamine, dihexylamine, diheptylamine, dioctylamine, etc. May be branched); monomethanolamine, monoethanolamine, monopropanolamine, monobutanolamine, monopentanolamine, monohexanolamine , Monoheptanolamine, monooctanolamine, monononanolamine, dimethanolamine, methanolethanolamine, diethanolamine, methanolpropanolamine, ethanolpropanolamine, dipropanolamine, methanolbutanolamine, ethanolbutanolamine, propanolbutanolamine, dibutanol And alkanolamines such as amines, dipentanolamines, dihexanolamines, diheptanolamines, dioctanolamines (the alkanol groups may be linear or branched); and mixtures thereof.

As the component (A), hydrogen phosphite (hydrogen phosphite) or hydrogenated thiophosphite in which R ³ is hydrogen in the formula (1) because it is excellent in the friction characteristics between the metal of the belt-pulley. Acid esters or amine salts and alkanolamine salts of these phosphorus compounds as described above are more preferably used.

  Specific examples of the component (A) include dimethyl hydrogen phosphite, diethyl hydrogen phosphite, dipropyl hydrogen phosphite, dibutyl hydrogen phosphite, dipentyl hydrogen phosphite, and dihexyl hydrogen phosphite. Dialkyl hydrogen phosphites (these alkyl groups may be linear or branched), diphenyl hydrogen phosphites, dicresyl hydrogen phosphites (cresyl groups may be o-, m- or p-), Dimethyl hydrogen thiophosphite, diethyl hydrogen thiophosphite, dipropyl hydrogen thiophosphite, dibutyl hydrogen thiophosphite, dipentyl hydrogen thiophosphite, Dialkyl hydrogen thiophosphites such as hexyl hydrogen thiophosphite (these alkyl groups may be linear or branched), diphenyl hydrogen thiophosphite, dicresyl hydrogen thiophosphite (the cresyl group is o- or m- Or p-), trialkyl phosphites such as trimethyl phosphite, triethyl phosphite, tripropyl phosphite, tributyl phosphite, tripentyl phosphite, trihexyl phosphite (these alkyl groups may be linear or May be branched), triphenyl phosphite, tricresyl phosphite (cresyl group may be o-, m- or p-), trimethylthiophosphite, triethylthiophosphite, tripropylthiophosphite Trialkylthiophosphites such as tributylthiophosphite, tripentylthiophosphite, trihexylthiophosphite (these alkyl groups may be linear or branched), triphenylthiophosphite, tricresylthiophosphite Phyto (the cresyl group may be o-, m-, or p-), or the above-described amine salts, alkanolamine salts, or mixtures of these phosphorus compounds can be exemplified. Dimethyl hydrogen phosphite, diethyl hydrogen phosphite, dipropyl hydrogen phosphite, dibutyl hydrogen phosphite, dipentyl hydrogen phosphite, dihexyl hydrogen phosphate Dialkyl hydrogen phosphites such as wite (these alkyl groups may be linear or branched), diphenyl hydrogen phosphite, dicresyl hydrogen phosphite (the cresyl group may be o-, m- or p-). Good) or a mixture thereof is particularly preferably used.

  In the lubricating oil composition for a metal belt type continuously variable transmission according to the present invention, the lower limit of the content of one or more (A) components arbitrarily selected is phosphorus element based on the total amount of the lubricating oil composition. The upper limit is 0.2% by mass, preferably 0.1% by mass as the amount of phosphorus element based on the total amount of the lubricating oil composition. It is. When the content of the component (A) is less than 0.005 mass% as the amount of phosphorus element based on the total amount of the lubricating oil composition, the effect of improving the friction coefficient between the belt and the pulley is poor, while the content is If the amount of phosphorus element exceeds 0.2% by mass on the basis of the total amount of the lubricating oil composition, the oxidation stability of the lubricating oil composition may decrease, and the durability of the sealing material or resin material may be adversely affected. Therefore, each is not preferable.

The component (B) in the lubricating oil composition for a metal belt type continuously variable transmission according to the present invention is an ashless dispersant.
In addition, although nitrogen content of (B) component is arbitrary, the lower limit of nitrogen content becomes like this. Preferably it is 0.2 mass%, More preferably, it is 0.8 mass%, On the other hand, the upper limit of nitrogen content The value is preferably 10.0% by mass, more preferably 5.0% by mass. If the nitrogen content of component (B) is less than 0.2% by mass, the lubricating oil composition may have insufficient clean dispersibility, whereas if the nitrogen content exceeds 10.0% by mass, the lubricating oil There is a risk of adversely affecting the abrasion resistance and oxidation stability of the composition.

Specific examples of the ashless dispersant as component (B) include nitrogen-containing compounds having at least one alkyl group or alkenyl group having 40 to 400 carbon atoms in the molecule or derivatives thereof. 1 type or 2 types or more arbitrarily chosen from can be mix | blended.
The alkyl group or alkenyl group may be linear or branched, but specific examples include olefin oligomers such as propylene, 1-butene and isobutylene, and ethylene and propylene co-oligomers. Examples thereof include branched alkyl groups and branched alkenyl groups.
The number of carbon atoms of the alkyl group or alkenyl group is arbitrary, but it is preferably 40 to 400, more preferably 60 to 350. If the alkyl group or alkenyl group has less than 40 carbon atoms, the solubility of the compound in the lubricant base oil may be reduced. On the other hand, if the alkyl group or alkenyl group has more than 400 carbon atoms, the lubricating oil composition may be reduced. Since the low-temperature fluidity | liquidity of a thing may deteriorate, it is unpreferable respectively.

Specific examples of the nitrogen-containing compound or derivative thereof include:
(B-1) A succinimide having at least one alkyl group or alkenyl group having 40 to 400 carbon atoms in the molecule, or a derivative thereof (B-2) an alkyl group or alkenyl group having 40 to 400 carbon atoms in the molecule Benzylamine having at least one thereof, or a derivative thereof (B-3) one or two selected from polyamines having at least one alkyl group or alkenyl group having 40 to 400 carbon atoms in the molecule, or derivatives thereof The above compound etc. are mentioned.

（（２）式中、Ｒ^４は炭素数４０〜４００、好ましくは６０〜３５０のアルキル基又はアルケニル基を示し、ａは１〜５、好ましくは２〜４の整数を示す。） More specific examples of the (B-1) succinimide include compounds represented by the following general formula (2) or (3).

(In the formula (2), R ⁴ represents an alkyl group or alkenyl group having 40 to 400 carbon atoms, preferably 60 to 350, and a represents an integer of 1 to 5, preferably 2 to 4).

（（３）式中、Ｒ^５及びＲ^６は、それぞれ個別に炭素数４０〜４００、好ましくは６０〜３５０のアルキル基又はアルケニル基を示し、ｂは０〜４、好ましくは１〜３の整数を示す。）

(In the formula (3), R ⁵ and R ⁶ individually represent an alkyl group or an alkenyl group having 40 to 400 carbon atoms, preferably 60 to 350, and b is an integer of 0 to 4, preferably 1 to 3. Is shown.)

  In addition, as succinimide, at the time of imidation, a so-called monotype succinimide having general formula (2) in which succinic anhydride is added to one end of polyamine, and succinic anhydride is added to both ends of polyamine. In addition, there is a so-called bis-type succinimide represented by the general formula (3), and any of these or a mixture thereof can be used as the component (B-1).

（（４）式中、Ｒ^７は炭素数４０〜４００、好ましくは６０〜３５０のアルキル基又はアルケニル基を示し、ｃは１〜５、好ましくは２〜４の整数を示している。） More specific examples of the (B-2) benzylamine include compounds represented by the general formula (4).

(In the formula (4), R ⁷ represents an alkyl group or alkenyl group having 40 to 400 carbon atoms, preferably 60 to 350 carbon atoms, and c represents an integer of 1 to 5, preferably 2 to 4).

  The production method of this benzylamine is not limited in any way. For example, after reacting polyolefin such as propylene oligomer, polybutene, ethylene-α-olefin copolymer with phenol to form alkylphenol, formaldehyde and diethylenetriamine are added thereto. It can be obtained by reacting polyamines such as triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine and the like by Mannich reaction.

（（５）式中、Ｒ^８は炭素数４０〜４００、好ましくは６０〜３５０のアルキル基又はアルケニル基を示し、ｄは１〜５、好ましくは２〜４の整数を示している。） More specific examples of the (B-3) polyamine include compounds represented by the general formula (5).

(In the formula (5), R ⁸ represents an alkyl group or alkenyl group having 40 to 400 carbon atoms, preferably 60 to 350 carbon atoms, and d represents an integer of 1 to 5, preferably 2 to 4).

  The production method of this polyamine is not limited in any way. For example, after chlorinating a polyolefin such as propylene oligomer, polybutene, ethylene-α-olefin copolymer, etc., it is then added to ammonia, ethylenediamine, diethylenetriamine, triethylenetetramine. It can be obtained by reacting polyamines such as tetraethylenepentamine and pentaethylenehexamine.

Specific examples of the derivatives of nitrogen-containing compounds include, for example, the above-mentioned nitrogen-containing compounds, monocarboxylic acids having 2 to 30 carbon atoms (fatty acids, etc.), oxalic acid, phthalic acid, trimellitic acid, pyro A so-called carboxylic acid-modified compound in which a part or all of the remaining amino group and / or imino group is neutralized or amidated by the action of a polycarboxylic acid having 2 to 30 carbon atoms such as merit acid; Examples thereof include sulfur-modified compounds in which a sulfur compound is allowed to act on such nitrogen-containing compounds; so-called boron-modified compounds obtained by modifying nitrogen-containing compounds as described above or their carboxylic acid-modified products or sulfur-modified products with boron compounds.
The method of modification with the boron compound is not limited in any way, and any method is possible. For example, the above-described nitrogen-containing compounds or derivatives thereof may be boric acid, borate, boric acid ester, or the like. Examples thereof include a method in which a boron compound is allowed to act to neutralize or amidate part or all of an amino group and / or imino group remaining in a nitrogen-containing compound or a derivative thereof.

  Specific examples of boric acid herein include orthoboric acid, metaboric acid, and tetraboric acid. Specific examples of the borate include, for example, alkali metal salts, alkaline earth metal salts or ammonium salts of boric acid, and more specifically, for example, lithium metaborate, lithium tetraborate, five Lithium borate such as lithium borate and lithium perborate; sodium borate such as sodium metaborate, sodium diborate, sodium tetraborate, sodium pentaborate, sodium hexaborate, sodium octaborate; metaboric acid Potassium borates such as potassium, potassium tetraborate, potassium pentaborate, potassium hexaborate and potassium octaborate; calcium metaborate, calcium diborate, tricalcium tetraborate, pentacalcium tetraborate, hexaborate Calcium borate such as calcium acid; magnesium metaborate, magnesium diborate, Trimagnesium pentoxide magnesium tetraborate, hexaborate magnesium such as magnesium borate; and ammonium metaborate, ammonium tetraborate, ammonium pentaborate, and ammonium borate, such as eight ammonium borate and the like. Examples of the boric acid ester include esters of boric acid and preferably an alkyl alcohol having 1 to 6 carbon atoms. More specifically, examples include boric acid monomethyl, boric acid dimethyl, boric acid trimethyl, boric acid monoethyl. Diethyl borate, triethyl borate, monopropyl borate, dipropyl borate, tripropyl borate, monobutyl borate, dibutyl borate, tributyl borate and the like.

  As the component (B) of the present invention, any of the above-mentioned nitrogen-containing compounds or derivatives thereof can be used, but when used in combination with the component (A), the belt-pulley of the metal belt type continuously variable transmission (B-1) Succinimide having at least one alkyl group or alkenyl group having 40 to 400 carbon atoms in the molecule, or a boron-modified product thereof, from the point of being excellent in the effect of improving the intermetallic friction coefficient between Preferably used.

  Furthermore, as the component (B) of the present invention, the boron-modified succinic acid is excellent in improving the friction coefficient between the belt and pulley of the metal belt type continuously variable transmission when used in combination with the component (A). It is desirable to use an imide or a mixture of boron-modified succinimide and boron-free succinimide. Although the boron content of this boron-modified succinimide is also arbitrary, from the point that it is excellent in the effect of improving the friction coefficient between the metal and the belt-pulley of a metal belt type continuously variable transmission, wear resistance and oxidation stability. The lower limit of the content is preferably 0.1% by mass, more preferably 0.4% by mass, while the upper limit of the content is preferably 4.0% by mass, more preferably 2%. 0.5% by mass.

  In the lubricating oil composition for a metal belt type continuously variable transmission according to the present invention, the lower limit value of the content of one or more components (B) selected arbitrarily is 0 based on the total amount of the lubricating oil composition. 0.05 mass%, preferably 0.1 mass%, while the upper limit of the content is 10.0 mass%, preferably 7.0 mass%, based on the total amount of the lubricating oil composition. When the content of the component (B) is less than 0.05% by mass based on the total amount of the lubricating oil composition, the effect of improving the friction coefficient between the belt and the pulley due to the combined use with the component (A) is poor, When the content of the component (B) exceeds 10.0% by mass, the low temperature fluidity of the lubricating oil composition is greatly deteriorated, which is not preferable.

  Moreover, it is preferable that the lubricating oil composition for a metal belt type continuously variable transmission according to the present invention further contains (C) an alkaline earth metal sulfonate having a total base number of 20 to 500 mgKOH / g. By using the component (C) in combination, it is possible to improve the metal-to-metal friction characteristics between the belt and the pulley in the metal belt type continuously variable transmission (reducing the sliding speed dependency of the friction coefficient).

  The lower limit of the total base number of the alkaline earth metal sulfonate of component (C) is 20 mg KOH / g, preferably 100 mg KOH / g, more preferably 150 mg KOH / g, while the upper limit is 500 mg KOH / g, Preferably it is 450 mgKOH / g. When the total base number is less than 20 mgKOH / g, the oxidation stability of the lubricating oil composition may be deteriorated. On the other hand, when the total base number exceeds 500 mgKOH / g, the storage stability of the lubricating oil composition is adversely affected. Respectively, which is not preferable. The total base number referred to here is 7. JIS K2501 "Petroleum products and lubricants-Neutralization number test method". It means the total base number by the perchloric acid method measured according to the above.

  More specifically, the alkaline earth metal sulfonate of the component (C) is, for example, an alkali of an alkyl aromatic sulfonic acid obtained by sulfonating an alkyl aromatic compound having a molecular weight of 100 to 1500, preferably 200 to 700. An earth metal salt is preferably used, and specific examples of the alkyl aromatic sulfonic acid include so-called petroleum sulfonic acid and synthetic sulfonic acid.

  As the petroleum sulfonic acid, there are generally used those obtained by sulfonating an alkyl aromatic compound of a lubricating oil fraction of mineral oil, so-called mahoganic acid that is produced as a by-product when white oil is produced. As the synthetic sulfonic acid, for example, an alkylbenzene having a linear or branched alkyl group, which is obtained as a by-product from an alkylbenzene production plant that is a raw material of a detergent or is obtained by alkylating a polyolefin with benzene, is used as a raw material. Sulphonated from this, or sulphonated from dinonylnaphthalene, etc. are used. The sulfonating agent for sulfonating these alkyl aromatic compounds is not particularly limited, but usually fuming sulfuric acid or sulfuric acid is used.

  In addition, the alkaline earth metal sulfonate of the component (C) is directly mixed with the above-mentioned alkyl aromatic sulfonic acid or the like as long as its base number is in the range of 20 to 500 mgKOH / g. Neutral salt (normal salt) obtained by reacting with alkaline earth metal bases such as sodium hydroxide or hydroxide, or once replacing alkali metal salts such as sodium salts and potassium salts with alkaline earth metal salts In the presence of basic salt or carbon dioxide gas obtained by heating excess alkaline earth metal salt or alkaline earth metal base (alkali earth metal hydroxide or oxide) in the presence of water And an overbased salt (superbasic salt) obtained by reacting a neutral salt (normal salt) with an alkaline earth metal base.

These reactions are usually carried out in a solvent (an aliphatic hydrocarbon solvent such as hexane, an aromatic hydrocarbon solvent such as xylene, a light lubricating base oil). Further, metal detergents are usually marketed in a state diluted with a light lubricating base oil or the like, and are also available, but generally the alkaline earth metal content is 1.0 to It is desirable to use 20% by mass, preferably 2.0 to 16% by mass.
Specific examples of the alkaline earth metal include calcium, magnesium, barium, and the like, but calcium is particularly preferable because it is more excellent in friction characteristics between the metal of the belt-pulley.

  In the lubricating oil composition for a metal belt type continuously variable transmission of the present invention, when one or more arbitrarily selected components (C) are used in combination, the lower limit of the content is the lubricating oil composition The amount of alkaline earth metal element based on the total amount is 0.01% by mass, preferably 0.03% by mass, while the upper limit is 0.5% as the amount of alkaline earth metal element based on the total amount of the lubricating oil composition. % By mass, preferably 0.2% by mass. When the content of the component (C) is less than 0.01% by mass as the amount of the alkaline earth metal element based on the total amount of the lubricating oil composition, the metal of the belt-pulley of the lubricating oil composition by the combined use of the component (C) On the other hand, when the content exceeds 0.5% by mass as the amount of alkaline earth metal element based on the total amount of the lubricating oil composition, the oxidation stability of the lubricating oil composition decreases. Each is not preferable because of fear.

  Moreover, it is preferable that the lubricating oil composition for a metal belt type continuously variable transmission according to the present invention further contains (D) calcium phenate having a total base number of 20 to 500 mgKOH / g. By using the component (D) in combination, it is possible to further improve the friction characteristics between the metal and the belt-pulley between the metal belt type continuously variable transmission (reducing the dependency of the friction coefficient on the sliding speed).

  The lower limit of the total base number of the component (D) calcium phenate is 20 mg KOH / g, preferably 100 mg KOH / g, more preferably 150 mg KOH / g, while the upper limit is 500 mg KOH / g, more preferably 450 mg KOH / g. When the total base number is less than 20 mgKOH / g, the oxidation stability of the lubricating oil composition may be deteriorated. On the other hand, when the total base number exceeds 500 mgKOH / g, the storage stability of the lubricating oil composition is adversely affected. Respectively, which is not preferable. The total base number referred to here is 7. JIS K2501 "Petroleum products and lubricants-Neutralization number test method". It means the total base number by the perchloric acid method measured according to the above.

  More specifically, as the calcium phenate of component (D), for example, an alkylphenol having at least one linear or branched alkyl group having 4 to 30 carbon atoms, preferably 6 to 18 carbon atoms, this alkylphenol Alkylphenol sulfide obtained by reacting sulfur with elemental sulfur or a calcium salt of methylenebisalkylphenol obtained by condensation dehydration reaction of this alkylphenol and acetone is preferably used.

  In addition, as long as the total base number is in the range of 20 to 500 mgKOH / g, the above-mentioned alkylphenol, alkylphenol sulfide, Mannich reaction product of alkylphenol, etc. are directly added to the calcium phenate of component (D). Neutral salt (normal salt) obtained by reacting with calcium base such as oxide or hydroxide, or once replacing alkali salt such as sodium salt or potassium salt with calcium salt, etc. Reaction of basic salts obtained by heating calcium salts and calcium bases (calcium hydroxides and oxides) in the presence of water and neutral salts (correct salts) with calcium bases in the presence of carbon dioxide. The overbased salt (superbasic salt) obtained by making it contain is included.

  These reactions are usually carried out in a solvent (an aliphatic hydrocarbon solvent such as hexane, an aromatic hydrocarbon solvent such as xylene, a light lubricating base oil). In addition, metal detergents are usually marketed in a state diluted with a light lubricating base oil or the like, and are available, but generally the calcium content is 1.0 to 20% by mass. It is desirable to use 2.0 to 16% by mass.

  In the lubricating oil composition for a metal belt type continuously variable transmission according to the present invention, when one or two or more (D) components arbitrarily selected are used in combination, the content thereof is arbitrary. The lower limit is 0.01% by mass, preferably 0.03% by mass as the amount of calcium element based on the total amount of the lubricating oil composition, while the upper limit is 0 as the amount of calcium element based on the total amount of the lubricating oil composition. 0.5% by mass, preferably 0.2% by mass. When the content of the component (D) is less than 0.01% by mass as the amount of calcium element on the basis of the total amount of the lubricating oil composition, the friction characteristics between the metal and the belt-pulley of the lubricating oil composition using the combined component (D) On the other hand, if the content exceeds 0.5% by mass as the amount of calcium element based on the total amount of the lubricating oil composition, the oxidation stability of the lubricating oil composition may be reduced. It is not preferable.

  In the present invention, only a specific amount of each of the component (A) and the component (B) is contained in the lubricating base oil, and further selected from the components (C) and / or (D) as necessary. The lubricating oil composition for a metal belt type continuously variable transmission that is excellent in the effect of improving the friction coefficient between the belt and the pulley can be obtained simply by using one or more compounds in combination. For the purpose of further improving performance, if necessary, an extreme pressure additive, a friction modifier, a viscosity index improver, a pour point depressant, an antioxidant, a corrosion inhibitor, a rubber swelling agent, an antifoaming agent, a coloring Various additives typified by agents may be contained alone or in combination of several kinds.

  Examples of the extreme pressure additive include zinc dithiophosphates, disulfides, sulfurized olefins, sulfurized fats and oils, phosphate esters and phosphites other than the component (A) of the present invention, and derivatives of these phosphorus compounds. And sulfur compounds and phosphorus compounds. One kind or two or more kinds of compounds arbitrarily selected from these can be contained in any amount, but the content is usually 0.01 to 5. based on the total amount of the lubricating oil composition. It is preferably 0% by mass.

However, it is desirable that the lubricating oil composition for a metal belt type continuously variable transmission according to the present invention does not substantially contain (E) zinc dithiophosphate. Here, “substantially free of component (E)” means that component (E) is not contained at all, or even if it is contained, the content of component (E) is the total amount of the lubricating oil composition. This means that the amount of zinc element is 0.03% by mass or less on the basis, and in the present invention, it is more preferable that the component (E) is not contained at all.
In the lubricating oil composition for a metal belt type continuously variable transmission according to the present invention, when (E) zinc dithiophosphate exceeds 0.03 mass% as the amount of zinc element based on the total amount of the lubricating oil composition, -Since the durability of the friction coefficient between metals between pulleys deteriorates and there is a large possibility that the friction coefficient decreases when the oil deteriorates, it is not preferable.

Specific examples of the component (E) include zinc dithiophosphate represented by the following general formula (6).

In ^{(6), R 9, R 10, R} 11 and ^{R 12} are each independently an alkyl group, an aryl group or an alkylaryl group having 7 to 18 carbon atoms having 1 to 18 carbon atoms.
Specific examples of the alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, an octyl group, a nonyl group, a decyl group, an undecyl group, a dodecyl group, a tridecyl group, and a tetradecyl group. , A pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, and the like, and an alkyl group having 3 to 8 carbon atoms is generally used. These alkyl groups include straight-chain and branched groups. They also include primary (primary) alkyl groups and secondary (secondary) alkyl groups.
When introducing R ⁹ , R ¹⁰ , R ¹¹ and R ¹² , a mixture of α-olefins may be used as a raw material. In this case, the compound represented by the formula (6) has an alkyl group having a different structure. It becomes a mixture of zinc dialkyldithiophosphate having.

Specific examples of the aryl group include a phenyl group and a naphthyl group.
Specific examples of the alkylaryl group include tolyl, xylyl, ethylphenyl, propylphenyl, butylphenyl, pentylphenyl, hexylphenyl, heptylphenyl, octylphenyl, nonylphenyl, decyl. A phenyl group, an undecylphenyl group, a dodecylphenyl group, and the like (these alkyl groups include both straight-chain and branched groups and all substituted isomers).

  As a friction modifier that can be used in combination with the lubricating oil composition for a metal belt type continuously variable transmission according to the present invention, any compound that is usually used as a friction modifier for lubricating oil can be used. Amine compound, fatty acid amide, fatty acid metal salt, phosphoric ester, phosphorous acid having at least one alkyl group or alkenyl group of 30, in particular, a linear alkyl group or linear alkenyl group having 8 to 24 carbon atoms in the molecule Examples include esters.

  As the amine compound, an aliphatic monoamine having a linear or branched alkyl group or alkenyl group having 6 to 30 carbon atoms, preferably a linear alkyl group or alkenyl group having 8 to 24 carbon atoms, carbon number An aliphatic polyamine having a linear or branched alkyl group or alkenyl group having 6 to 30 carbon atoms, preferably a linear alkyl group or alkenyl group having 8 to 24 carbon atoms, or these aliphatic (poly) amines Examples include alkylene oxide adducts. As fatty acid amides, fatty acids having a linear or branched alkyl or alkenyl group having 6 to 30 carbon atoms, preferably a linear alkyl or alkenyl group having 8 to 24 carbon atoms, and aliphatic monoamines Or an amide with an aliphatic polyamine can be exemplified. The fatty acid metal salt includes an alkaline earth of a fatty acid having a linear or branched alkyl or alkenyl group having 6 to 30 carbon atoms, preferably a linear alkyl or alkenyl group having 8 to 24 carbon atoms. Examples thereof include metal salts (magnesium salts, calcium salts, etc.), zinc salts and the like. As the phosphate ester, 3 linear or branched alkyl groups or alkenyl groups having 6 to 30 carbon atoms, preferably 3 linear alkyl groups or alkenyl groups having 8 to 24 carbon atoms in one molecule. Examples thereof include phosphoric acid triesters and acidic phosphoric acid esters (acid phosphates) having one or two alkyl groups or alkenyl groups in one molecule. As the phosphite ester, a linear or branched alkyl group or alkenyl group having 6 to 30 carbon atoms, preferably a linear alkyl group or alkenyl group having 8 to 24 carbon atoms in one molecule. Examples thereof include a phosphorous acid triester having a single number, a hydrogenated phosphite having one or two alkyl groups or alkenyl groups in one molecule (hydrogen phosphite), and the like.

  In the present invention, one kind or two or more kinds of compounds arbitrarily selected from these friction modifiers can be contained in any amount, but usually the content thereof is a lubricating oil composition. It is desirable that the content is 0.01 to 5.0% by mass, preferably 0.03 to 3.0% by mass based on the total amount.

  The viscosity index improver that can be used in combination with the lubricating oil composition for a metal belt type continuously variable transmission according to the present invention is specifically a copolymer of one or more monomers selected from various methacrylates. Or a so-called non-dispersed viscosity index improver such as a hydrogenated product thereof, or a so-called dispersed viscosity index improver obtained by copolymerizing various methacrylic acid esters containing a nitrogen compound can be exemplified. Specific examples of other viscosity index improvers include non-dispersed or dispersed ethylene-α-olefin copolymers (the α-olefin can be exemplified by propylene, 1-butene, 1-pentene, etc.) and hydrides thereof. , Polyisobutylene and hydrogenated products thereof, styrene-diene hydrogenated copolymer, styrene-maleic anhydride ester copolymer, and polyalkylstyrene.

The molecular weight of these viscosity index improvers needs to be selected in consideration of shear stability. Specifically, the number average molecular weight of the viscosity index improver is, for example, 5,000 to 150,000, preferably 5,000 to 35,000 in the case of dispersed and non-dispersed polymethacrylates. In the case of isobutylene or a hydride thereof, 800 to 5,000, preferably 1,000 to 4,000, and in the case of an ethylene-α-olefin copolymer or a hydride thereof, 800 to 150,000, preferably The thing of 3,000-12,000 is preferable.
Of these viscosity index improvers, when an ethylene-α-olefin copolymer or a hydride thereof is used, a lubricating oil composition having particularly excellent shear stability can be obtained.
In the present invention, one or two or more compounds arbitrarily selected from these viscosity index improvers can be contained in any amount, but the content thereof is usually a lubricating oil composition. It is desirable that it is 0.1-40.0 mass% on the basis of the total amount of things.

Antioxidants that can be used in combination with the lubricating oil composition for metal belt continuously variable transmissions of the present invention can be used as long as they are generally used in lubricating oils such as phenolic compounds and amine compounds. It is. Specifically, alkylphenols such as 2-6-di-tert-butyl-4-methylphenol, and bisphenols such as methylene-4,4-bisphenol (2,6-di-tert-butyl-4-methylphenol). , Naphthylamines such as phenyl-α-naphthylamine, dialkyldiphenylamines, (3,5-di-tert-butyl-4-hydroxyphenyl) fatty acid (propionic acid etc.) and mono- or polyhydric alcohols such as methanol, octa Examples include esters with decanol, 1,6-hexadiol, neopentyl glycol, thiodiethylene glycol, triethylene glycol, pentaerythritol, and the like.
In the present invention, one kind or two or more kinds of compounds arbitrarily selected from these antioxidants can be contained in any amount, but the content thereof is usually a lubricating oil composition. It is desirable that it is 0.01-5.0 mass% on the basis of the total amount.

Examples of the corrosion inhibitor that can be used in combination with the lubricating oil composition for a metal belt type continuously variable transmission according to the present invention include benzotriazole, thiadiazole, and imidazole compounds.
In the present invention, one or two or more compounds arbitrarily selected from these corrosion inhibitors can be contained in any amount, but the content is usually determined by the lubricating oil composition. It is desirable that it is 0.01-3.0 mass% on the basis of the total amount.

Examples of the antifoaming agent that can be used in combination with the lubricating oil composition for a metal belt type continuously variable transmission according to the present invention include silicones such as dimethyl silicone and fluorosilicone.
In the present invention, one or two or more compounds arbitrarily selected from these antifoaming agents can be contained in any amount, but the content is usually the lubricating oil composition. It is desirable that it is 0.001-0.05 mass% on the basis of the total amount.

  The colorant that can be used in combination with the lubricating oil composition for a metal belt type continuously variable transmission according to the present invention is optional and can contain any amount, but the content is usually the total amount of the lubricating oil composition. It is desirable that it is 0.001-1.0 mass% on the basis.

  Hereinafter, the content of the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited thereto.

[Test 1]
For the comparison having the lubricating oil compositions for belt type continuously variable transmissions according to the present invention having the compositions shown in Examples 1 to 3 of Table 1, respectively, and having the compositions shown in Comparative Examples 1 to 3 of Table 2 Each lubricating oil composition was prepared.
In order to evaluate the friction characteristics between the belt and the pulley of the metal belt type continuously variable transmission of each adjusted composition, “Standard Test Method for Calibration and Operation of Falex Block-on-” prescribed in ASTM D2714-94 In accordance with “Ring Friction and Wear Testing Machine”, the LFW-1 friction test was performed under the following conditions, and the friction coefficient was determined from the friction force measured at each sliding speed. The results are shown in FIG.

(Test conditions)
Ring: Falex S-10 Test Ring (SAE 4620 Steel)
Block: Falex H-60 Test Block (SAE 01 Steel)
Oil temperature: 100 ° C
Test piece contact part maximum hertz pressure: 0.287 GPa
Sliding speed: 0 to 25 cm / s

  As is clear from the results of FIG. 1, the lubricating oil compositions of Examples 1 to 3 containing the component (A) and the component (B) according to the present invention were compared using a phosphorus compound other than the component (A). It can be seen that the coefficient of friction between metals is high compared to the composition of the example.

[Test 2]
In the lubricating oil composition for a metal belt type continuously variable transmission according to the present invention, in order to evaluate the influence on the friction characteristics between metals by the combined use of (C) alkaline earth metal sulfonate, Examples 4 to 8 in Table 3 are shown. Each lubricating oil composition having a composition was prepared.
About the adjusted compositions (compositions shown in Examples 4 to 8) and the composition of Example 1 shown in Table 1 and Comparative Example 1 shown in Table 2, a belt of a metal belt type continuously variable transmission -In order to evaluate the friction characteristics between the metals between pulleys, the LFW-1 friction test was performed under the same conditions as in Test 1 (only the sliding speed was changed to 0 to 100 cm / s), and measured at each sliding speed. The coefficient of friction was determined from the friction force. The results are shown in FIG.
As is apparent from the results of FIG. 2, in the lubricating oil composition for a metal belt type continuously variable transmission according to the present invention, (C) the alkaline earth metal sulfonate is used in combination to greatly improve the friction characteristics between metals (friction coefficient). It can be seen that (depending on the sliding speed) can be reduced.

[Test 3]
In the lubricating oil composition for a metal belt type continuously variable transmission according to the present invention, in order to evaluate the influence on the friction characteristics between metals by the combined use of (D) calcium phenate, the compositions shown in Examples 9 to 11 in Table 4 are used. Each lubricating oil composition was prepared.
About the adjusted compositions (compositions shown in Examples 9 to 11) and the composition of Example 1 shown in Table 1 and Comparative Example 1 shown in Table 2, the belt of a metal belt type continuously variable transmission In order to evaluate the friction characteristics between the metals between the pulleys, the LFW-1 friction test was performed under the same conditions as in Test 1 (only the sliding speed was changed to 0 to 100 cm / s), and the friction measured at each sliding speed. The coefficient of friction was determined from the force. The results are shown in FIG.
As is clear from the results of FIG. 3, in the lubricating oil composition for a metal belt type continuously variable transmission of the present invention, by using (D) calcium phenate in combination, It can be seen that the inter-friction characteristics can be greatly improved (the friction speed dependence of the friction coefficient is reduced).

[Test 4]
In the lubricating oil composition for a metal belt type continuously variable transmission according to the present invention, in order to investigate the influence on the friction characteristics between metals by the combined use of (E) zinc dithiophosphate, it has the compositions shown in Examples 12 to 14 of Table 5. Each lubricating oil composition was prepared.
For the prepared compositions (compositions shown in Examples 12 to 14), the same conditions as in Test 1 were used for the new oil and its deteriorated oil in order to evaluate the friction characteristics between the belt and the pulley during deterioration. (However, the LFW-1 friction test was performed with the maximum Hertz pressure at the contact portion of the test piece changed to 0.574 GPa and the sliding speed was changed to 0 to 100 cm / s), and the friction force measured at each sliding speed was used. The coefficient of friction was determined.
The deteriorated oil conforms to “4. Lubricating oil oxidation stability test method” of “Lubricating oil-oxidation stability test method” prescribed in JIS K2514-1993, and the test temperature is 150 ° C. It was created by deteriorating under the condition of a test time of 144 hours.
The results with the new oil are shown in FIG. 4, and the results with the deteriorated oil are shown in FIG.
As is apparent from the results of FIGS. 4 and 5, in the lubricating oil composition for a metal belt type continuously variable transmission according to the present invention, (E) zinc dithiophosphate is contained in an amount of elemental zinc exceeding 0.03% by mass. Then, it turns out that the durability of the friction coefficient between metals deteriorates greatly.

It is a figure which shows the relationship between a friction coefficient and a sliding speed. It is a figure which shows the relationship between a friction coefficient and a sliding speed. It is a figure which shows the relationship between a friction coefficient and a sliding speed. It is a figure which shows the relationship between a friction coefficient and a sliding speed. It is a figure which shows the relationship between a friction coefficient and a sliding speed.

Claims (5)

In lubricating base oil,
(A) 0.005 to 0.2% by mass of at least one phosphorus compound represented by the following general formula (1) or a derivative thereof as a phosphorus element amount based on the total amount of the composition,

(In the formula (1), R ¹ and R ² each independently represent an alkyl group having 1 to 6 carbon atoms, a phenyl group or a cresyl group, R ³ represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, A phenyl group or a cresyl group, and X ¹ , X ² and X ³ each independently represent an oxygen atom or a sulfur atom)
And (B) an ashless dispersant having a nitrogen content of 0.2% by mass or more, 0.05 to 10.0% by mass based on the total amount of the composition,
A lubricating oil composition for a metal belt type continuously variable transmission, comprising:   2. The lubricating oil composition for a metal belt type continuously variable transmission according to claim 1, wherein all or part of the component (B) is a boron-modified succinimide. 3.   The lubricating oil composition for a metal belt type continuously variable transmission according to claim 1 or 2, further comprising (C) an alkaline earth metal sulfonate having a total base number of 20 to 500 mgKOH / g, based on the total amount of the composition. A lubricating oil composition for a metal belt type continuously variable transmission, comprising 0.01 to 0.5% by mass of a metal element.   The lubricating oil composition for a metal belt type continuously variable transmission according to claim 1, 2 or 3, further comprising: (D) calcium phenate having a total base number of 20 to 500 mgKOH / g, based on the total amount of the composition. A lubricating oil composition for a metal belt type continuously variable transmission, characterized by containing 0.01 to 0.5% by mass.   The metal belt type continuously variable lubricating oil composition for a metal belt type continuously variable transmission according to claim 1, 2, or 3, characterized by being substantially free of (E) zinc dithiophosphate. Lubricating oil composition for transmission.

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